颈椎单椎体次全切除撑开植骨后即刻运动稳定性测定

An investigation of immediate biomechanical stability of lower cervical spine after subtotal corpectomy with distraction and grafting

目的 观察中下颈椎前路单椎体次全切除减压后不同撑开高度支撑植骨对颈椎即刻运动稳定性的影响 ,为临床手术提供参考。方法 采用 6具新鲜成人尸体颈椎标本 ,对完整状态、C5椎体次全切除减压后 ,C4和C6椎体间以减压槽高度为基础依次撑开 0、2、4、6、8mm支撑植骨 6种状态进行生物力学测试 ,在脊柱三维运动实验机上记录C4、C5和C6椎体的三维运动 ,使用计算机图像处理软件和脊柱运动分析程序测量C4～ 5和C5～ 6节段在各种载荷条件下三维六自由度的运动范围。结果 减压后椎体间撑开 4mm、6mm植骨状态下手术节段的即刻运动稳定性比完整状态及不撑开植骨状态增加 (P <0 0 5 )。结论 中下颈椎单椎体次全切除减压后 ,撑开植骨对手术节段的即刻运动稳定性有重要作用 ,适当的上下椎体间撑开高度为 4～ 6mm。

Objective To establish the reference value of the strut graft height for clinic by analyzing the effects of change in strut graft height on the immediate biomechanical stability of the lower cervical spine on which single vertebra subtotal corpectomy and strut graft reconstruction with different height graft were performed. Methods 6 fresh human cervical spine specimen of young cadaver were used for biomechanical test in the 6 serial conditions: intact, C 5 subtotal corpectomy and grafting respectively with a distraction of 0, 2, 4, 6 and 8 mm between C 4 and C 6 vertebrae. Parameters of three dimensional motion were determined by sterophotography. The stability of C 4～5 and C 5～6 motion segment in different conditions was analyzed by computer. Results Compared with the intact condition or strut grafted without distraction, the global immediate stability of the operated segments was significantly increased by grafting with a distraction over 4 mm between the adjacent vertebrae ( P <0 05). Conclusion Strut graft with an appropriate distraction after subtotal corpectomy plays an important role in the global immediate biomechanic stability of the lower cervical spine. The proper graft height after single vertebra subtotal corpectomy may be 4～6 mm above baseline height between the superior and inferior vertebrae.